BECE Mathematics 2019 Paper

Mean = Sum of Numbers/Total number of numbers(items)When you count the numbers, $5, 2x, 4$ and 3 , you will get 4 , hence total number of numbers $=4$Mean $=5$Sum means add all the numbers$\Rightarrow 5=\frac{5+2x+4+3}{4}$Solve for $x$Get rid of the fraction by multiplying both sides of the equation by the LCM of the denominators (1 and 4). The LCM of the denominators is 4 hence multiply both sides by 4 $\;5=\frac{5}{1}$$\; \Rightarrow 5 \times 4 = 5+2x+4+3$$\;20=5+2x+4+3$$\;20=5+4+3+2x$$\;20=12+2x$$\;20-12=2x$$\;8=2x$Divide both sides by 2$\; \frac{8}{2} = \frac{2x}{2}$$\;4=x$$\; \Rightarrow x=4$